Known roller skate brake pads fall into one of two general classes. Those pads in the first class provide a full facial engagement between the ultimately maximum available pad braking surface and the skating surface from the time of initial brake engagement throughout its life. Pads in the second class are structured such that upon initial brake engagement, only a small portion of the ultimately maximum available braking surface makes contact with the skating surface, and full facial engagement of the ultimately maximum available braking surface with the skating surface is not achieved until substantial brake pad wear has occurred. Full facial engagement of the maximum available braking surface throughout the use life of the pad is generally preferred since it maximizes the amount of braking available to the skater from the first application of the brake until the pad is fully worn out.
With many prior art roller skate brake pads, the contact area between the pad braking surface and the skating surface does not change substantially during braking activity, except for short intervals during a phenomenon which will be called rebound and except for the relatively insubstantial change due to abrasion that actually occurs during braking activity. Thus, except for rebound, the brake is either completely engaged or completely disengaged during use and the ability of the skater to slow down or stop is generally determined by the amount of force the skater is able to bring to bear to urge the pad against the skating surface. When the available braking surface of most pads is totally engaged with the skating surface, rebound can occur, and the skater must act appropriately to prevent or control that rebound and the intermittent interruptions of braking that can come with rebound.
Rebound occurs when the brake is engaged with too much force by the skater and as a result it bounces away from the roadway surface because the skater either has insufficient strength to prevent the bounce or has insufficient skill to control it.
Rebound also occurs when the brake pad undergoes deformation during braking activity. That is, when a skater applies the brake, the brake pad will begin to elastically deform rearwardly upon its engagement with the skating surface due to the frictional forces generated between the engaged surfaces. This deformation takes the form of an outward, rearwardly extending, C-shaped curvature at the trailing edge of the brake pad and, in general, a rearward displacement of that portion of the pad lying near the pad braking surface away from the portions of the brake pad thereabove. During braking, the upper front corner of the pad may be rotated downwardly and stretched away from the brake housing somewhat as braking forces urge the pad rearwardly. As this occurs, the leading edge of the pad tends to rotate rearwardly and become the predominant braking portion of the pad. This causes the leading edge to compress inwardly towards the center of the pad and these compressive forces dominate the applied braking forces. This stretching or deformation will continue until the elastic limit of the brake pad is reached, at which time the pad generally will rebound to its original configuration after first disengaging from the skating surface. Such stretching, disengagement, and rebound may occur several times per second during braking conditions. Prior art brake pads are subject to this elastic rebound type oscillation, the major components of which are the inward compressive forces experienced by the leading edge of the pad, resulting in a diminishing of braking efficiency. Until the present invention, this problem was not recognized and no solution was known.
An associated problem is that while full facial engagement between the pad's braking surface and the riding surface is important for maximum braking efficiency, it is desirable that this maximum engagement with the surface and the resulting immediate onset of full braking not be so abrupt as to de-stabilize the skater. Accordingly, it is desirable to have the brake engage in a manner in which maximum braking force does not occur instantaneously with brake engagement so as to allow a skater, particularly an inexperienced skater, to acclimate himself to the deceleration before it is maximized. Until the present invention, no skate braking system allowed both full facial engagement and gradual braking surface engagement. Gradual braking could only be achieved by the skater cautiously applying the braking surface to the riding surface with carefully controlled amounts of braking force. Such control, however, required experience and was very challenging to inexperienced skaters.
It would be desirable to have a roller skate brake that is less dependent for proper braking upon the strength and experience of the individual skater; that would provide all skaters with greater control over braking; and that would provide a skater with a substantially full facial engagement of the brake pad braking surface with the skating surface throughout the use life of the brake pad while avoiding the effects of abrupt engagement and rebound. Preferably, such a brake should be capable of being retro-fitted to existing brakes and should be useful on both conventional and in-line types of roller skates. The present invention provides an effective solution to these deficiencies in roller skate brakes.